This invention relates to nonrefillable or single use valves used in pressurized systems. More particularly, the invention relates to a nonrefillable valve especially adapted for use with pressurized vessels or containers wherein the construction of the valve allows the pressure container to be filled once, and then selectively discharged; however, subsequent refill of the pressure container is prevented.
Valves are commonly used to control the discharge of fluid from a pressure container or vessel. Typically, such valves include a handle or some other means by which a user can selectively control discharge of the container. Pressure containers may contain any number of products such as butane, propane, refrigerant gas, or any number of other types of industrial gases.
Due to governmental regulations in the United States, pressure containers containing refrigerants may only be filled once. Thus, such pressure containers can be initially charged or filled with the refrigerant; however, once the refrigerant has been discharged from the container, the container may not be refilled again.
There are a number of prior art valves which exist not only for use with non-refillable containers, but also refillable containers. One group of patents representative of valves which are used in conjunction with nonrefillable containers include patents assigned to Amtrol, Inc., of West Warwick, R.I. One specific example includes the U.S. Pat. No. 4,813,375. This reference discloses a nonrefillable valve including a housing with a central bore, and three distinct portions within the central bore of particular diameters. The lower portion of the central bore is narrower than a middle portion which in turn is narrower than an upper portion. The lower end of the valve housing sealingly engages the pressure container. A valve stem is rotatably positioned in the upper portion of the central bore. The valve stem itself includes a vertical bore formed in its bottom portion. A resilient valve sealing member is slidably received in the bore of the valve stem. When the pressure container is filled, a top rim portion of the sealing member is pressingly positioned in the upper portion of the central bore. After filling, the valve sealing member is pushed downward into the middle portion which allows the valve to contact a seating surface thus sealing the pressure container. A non-compressed top rim of the sealing member is wider than the upper portion of the central bore, which prevents the sealing member from moving back up into the upper portion of the central bore. If an attempt is made to refill the container, the sealing member engages the seating surface thus preventing refill. Additional U.S. patents disclosing similar valves include the U.S. Pat. Nos. 5,295,502; 4,573,611; and 5,036,876.
While the foregoing references may be adequate for their intended purposes, there is still a need for a valve of simple and reliable construction which prevents refilling of a pressure container.
One object of the present invention is to provide a nonrefillable valve for pressure containers, for example, cylinders used in industrial applications to hold and store pressurized industrial gas. Another object of the invention is to provide a valve which easily permits discharge of the pressure container, but will automatically prevent refilling of the container without the user or operator of the valve having to further manipulate the valve. Another object of the invention is to provide the above described functionality with a valve of simple and reliable construction.
The structure of the valve of the present invention includes a valve body having a longitudinal chamber extending therethrough. A lower portion of the chamber communicates with the opening or orifice of a pressure container to which the valve is attached. A valve stem is positioned within the chamber. A handle is integral with an upper portion of the valve stem providing a means for a user to manipulate the positioning of the valve stem within the chamber. A valve core is slidably received in a bore formed on the lower end of the valve stem. The valve core includes a sealing member formed on the lower portion thereof. A nozzle attaches to the valve body, the nozzle including an orifice or passageway which communicates with the chamber of the valve body. A transverse opening formed on the sidewall of the valve body communicates between the nozzle passageway and the chamber.
An inner concentric rim, flange, or protrusion is formed on the internal sidewall of the chamber adjacent the passageway of the nozzle. When the empty pressure container is to be filled with a pressurized fluid, the valve core is placed in a first open position wherein a larger diameter portion of the valve core flange resides in the chamber above the inner concentric rim. In this first position, fluid may flow through the nozzle passageway into a lower portion of the chamber, and then through an opening or orifice communicating with the pressure container. After the pressure container has been filled, the handle is operated to move the valve stem downwardly within the valve body thus forcing the valve core flange beyond the inner concentric rim. The valve stem can be moved to force the sealing member of the valve core against a valve seat which seals the pressure container, thus defining a second closed position.
In order to evacuate or empty the contents of the pressure container, the handle is unscrewed thereby raising the valve stem, and allowing the sealing member to be unseated from engagement with the valve seat. Fluid pressure raises the valve core allowing the fluid to escape the pressure container back through the lower portion of the chamber and back through the nozzle passageway.
Refilling of the pressure container is prevented even when the valve stem is raised to allow the sealing member to be unseated. This is accomplished due to contact between the upper surface of the valve core flange and the inner concentric rim, thereby preventing the valve core flange from being positioned above the inner concentric rim. A third position is therefore defined when the valve stem is raised to allow the valve core to be unseated from the valve seat. In this third position, the majority of the area of the nozzle passageway communicating with the chamber resides above the valve core flange. In other words, a transverse opening into the chamber is created where the nozzle intersects the internal sidewall of the chamber, and the majority the cross-sectional area of this opening lies above the inner concentric rim, and likewise, above the valve core flange. Therefore, a pressurized flow of fluid entering the nozzle passageway results in a greater majority of such flow entering the portion of the chamber above the valve core flange, thus forcing the flange downwardly, and thereby resulting in the sealing member engaging the valve seat. Because the valve core is freely slidable within the bore of the valve stem, there is no means by which to operate the handle in order to place the valve core back in its first position. In this manner, the valve of the present invention functions as a check valve to prevent refill of the container.
In addition to an inner concentric rim, other constricting structures can be provided to prevent the valve core from returning to its first position once a user closes the valve. For example, one or more arc like segments, or one or more protrusions may extend from the inner wall of the valve body into the chamber, thereby constituting the constriction which must be overcome by the particular sized valve core flange.
The valve core may be one integral unit made of a resilient material, such as natural or synthetic rubber. Alternatively, the valve core may include a valve core body, and a sealing member which includes a resilient sealing surface for engagement with the valve seat. The valve core flange can also be shaped to accommodate the particular constriction formed within the chamber. The valve core flange can be shaped or configured allowing it to be compressed or moved downwardly past the constriction without undue force, yet the valve core flange configuration makes it much more difficult to return the valve core to its first position. For example, the lower end of the valve core flange can be slightly tapered, while the upper end can have a distinct edge or corner preventing it from being easily forced upwardly beyond the constriction.
Other features and advantages of the invention will become apparent from a review of the drawings, taken in conjunction with the following written description.